feat(frontend/forms): make all dialogs that can be cancelled closeable by...

feat(frontend/forms): make all dialogs that can be cancelled closeable by pressing the escape key on the keyboard or clicking outside of the dialog

Previously, there was a distinction between `onClose` (which would close a dialog if the escape key was pressed or a click outside the dialog was performed)
and `cancel`.
It does not really make sense to differentiate those cases, since there is not really a difference between cancelling a dialog and
closing it using the escape key / clicking outside of the dialog (as this essentially also cancels the dialog).
Now, `cancelButtonProps` and `onClose` was merged into one `onClose`, as soon as `onClose` is defined, the cancel button is added
and the dialog can be closed using the escape key / clicking outside of the dialog.